Sheet piler

ABSTRACT

A two station piling machine for metal sheets which comprises an upright frame on which there are supported laterally spaced, overhead belt conveyors having magnets for holding the sheets on the belts while they are advanced over and then released for deposit on one of two inline hoist tables, or passed through the machine as determined by the operator, each piling area having associated back stop and end stop mechanisms together with laterally adjustable side guides and finger mechanisms for temporarily supporting the sheets while a previously formed pile of the sheets is removed from beneath the same, and the finger mechanisms being mounted on the adjustable side guide mechanisms and also on the end stop and back stop mechanisms so as to provide support about the entire periphery of the sheets which are accumulated on the finger mechanisms.

United States Patent 1191 Buccicone Mar. 26, 1974 SHEET FILER Primary Examiner-Evon C. BlunIk 75 Inventor; n Bucdcone Gary, 1 Assistant Examiner Bruce H. Stoner, Jr.

Attorney, Agent, or Firm-Guy A. Greenawalt [73] Asslgneez Bucciconi Engineering Co., Inc.,

Gary, Ind. [57] ABSTRACT Filedi p 1971 A two station piling machine for metal sheets which comprises an upright frame on which there are sup- [ZI] Appl' No" 180,642 ported laterally spaced, overhead belt conveyors having magnets for holding the sheets on the belts while 214/6 271/64, they are advanced over and then released for deposit 271/193, 271/218, 271/224 on one of two inline hoist tables, or passed through Int. the machine as determined the operator each of Search A, 64, 68, area having associated back stop and end Stop 214/6 DK mechanisms together with laterally adjustable side guides and finger mechanisms for temporarily supportl References Cited ing the sheets while a previously formed pile of the UNITED STATES PATENTS sheets is removed from beneath the same, and the fin- 3,410,421 11/1968 01011 214/6 DK ger mechanisms being mounted the adjustable side 2,393,573 7/1959 Buccicone 271/63 X guide mechanisms and also on the end stop and back 3,522,943 8/1970 Swanson 1. 271/016. 7 Stop mechanisms so as to provide support about the 2,761,682 9/1956 Buccicone 271/86 entire periphery of the sheets which are accumulated 3,297,318 H1967 Knecht 271/68 n the finger mechanisms 3 Claims, 14 Drawing Figures PMENTEDMARZS I974 3.799540 sum 1 BF 8 PATENTED MARZB I974 SHEET 2 BF 8 PATENTED MAR 2 6 [974 SHEEI 6 UP cab/99540 ATENTEDMAR26 i974 SHEET 5 [IF 8 MIENTEU MR 2 6 I974 SHEET 7 [IF 8 SHEET PILER This invention relates to mechanisms for piling metal sheets as they are received from a high speed processing line and is more particularly concerned with improved edge aligning and sheet supporting devices for such mechanisms.

In the handling of metal sheets, particularly in the processing of such sheets in the steel mills where they are delivered from a high speed processing line, such as, from a continuous shear, which is capable of delivering cut sheets at a relatively high rate, piling of the sheets mechanically in a rapid and efficient manner without damage to the sheets has presented problems. Apparatus has been designed for this purpose and one such apparatus is disclosed in US. Pat. No. 2,893,573, dated July 7, 1959. In this machine and in other machines of a similar character, the sheets are accumulated on a suitable support, such as, a roller conveyor section or elevator or hoist beneath the delivery conveyor, and at intervals the accumulated pile of sheets is removed from the machine enabling a new pile to be started. With the machine disclosed in US. Pat. No. 2,893,573 it has been possible to remove the accumulated pile of sheets without interrupting the flow of sheets to the piler mechanism. Experience in the use of this machine has indicated the desirability of providing an improved arrangement for aligning the sheets and for temporarily supporting them while a previously accumulated pile is removed from the machine and it is a general object of this invention to provide a machine having improved sheet edge aligning and supporting features.

It is a more specific object of the invention to provide a mechanism for piling metal sheets which are delivered by an overhead conveyor wherein there is an improved arrangement for temporarily supporting the sheets at points about the periphery thereof so as to enable a new pile to be started while the pile formed by the preceding sheets is being removed from the machine, without any interruption in the delivery of the sheets to the piling machine.

It is a still more specific object of the invention to provide a sheet piling mechanism wherein the sheets are delivered to the mechanism in a continuous stream by an overhead conveyor which is operable to release the successive sheets for deposit on a pile, wherein the pile of sheets is received on a movable platform, and wherein the mechanism is provided with temporary sheet supporting means which may be interposed in the path of the sheets as they settle onto the pile to temporarily support the sheets and start a new pile while the sheets which have been accumulated previously are removed from beneath the same and the support platform is cleared so as to receive the sheets which have accumulated on the temporary supporting means and start a new pile.

It is another object of the invention to provide a mechanism for piling metal sheets which are delivered to the piling machine in a continuous stream by an overhead conveyor with the sheets being released for piling at one or more points beneath the conveyor wherein the mechanism comprises a vertically movable platform mounted in spaced relation below the conveyor for receiving the sheets as they are released therefrom and temporary sheet supporting members which are mounted for supporting the sheets at points spaced about the entire periphery thereof and which are movable into and out of sheet supporting position between the conveyor and the platform, the temporary sheet supporting members being adapted to be positioned to receive the initial sheets in a new pile while the previously accumulated pile of sheets is removed from the supporting platform and the latter is adjusted to receive a new pile upon the temporary sheet supporting members being moved out of sheet supporting position.

It is another object of the invention to provide a sheet piling machine wherein the sheets are delivered by an overhead magnetic conveyor and deposited on an ele' vator mechanism between oppositely disposed side guide members and between end] stop and back stop members, the side guide members being adjustably mounted for movement laterally of the piling area and wherein movable fingers for temporarily supporting the sheets are provided on the side guide members, the end stop member and the back stop member which fingers are adapted to be positioned in the path of the sheets as they are released by the conveyor and dropped between the guide members so as to temporarily support the sheets while the pile of sheets which has accumulated on the elevator mechanism is removed therefrom and the elevator is repositioned for supporting the succeeding sheets and permitting the temporary sheet supporting members to be withdrawn to an inoperative position.

These and other objects and advantages of the invention will be apparent from a consideration of the sheet piling machine which is shown by way of illustration in the accompanying drawings wherein:

FIG. 1 is a plan view, with portions broken away, of a two station sheet piling machine which incorporates therein edge guides and sheet supporting mechanisms embodying the principal features of the invention;

FIG. 2 is a side elevation, with portions broken away, of the sheet piling machine shown in FIG. 1;

FIG. 3 is a cross sectional view, to an enlarged scale, the view being taken on the line 3-3 of FIG. 1;

FIG. 4 is a cross sectional view, to an enlarged scale, the view being taken on the line 44 of FIG. 1;

FIG. 5 is a plan view, with portions broken away or omitted, the view showing one of the side guide mechanisms, the view being taken generally on the line 5--5 of FIG. 3 and on a larger scale;

FIG. 6 is an elevational view of the side guide mechanism shown in FIG. 5, the view being taken generally on the line 6-6 of FIG. 3, with portions broken away and other portions omitted;

FIG. 7 is a cross section taken generally on the line 7-7 of FIG. 5, to an enlarged scale;

FIG. 8 is a plan view taken on the line 88 of FIG. 7 which shows a portion of the apparatus shown in FIG.

5, to an enlarged scale;

FIG. 9 is a cross section taken on the line 9-9 of FIG. 5, to an enlarged scale;

FIG. 10 is a fragmentary longitudinal section taken on the line 10-10 of FIG. 3, to an enlarged scale and with portions omitted;

FIG. 11 is a partial side elevation showing the end stop mechanism at the end of the machine, the view being taken from the far side of the machine, as shown in FIG. 2, and on an enlarged scale;

FIG. 12 is a sectional view taken on the line l2l2 of FIG. 11, on an enlarged scale;

.13 is an t als d mtism fthssyisten. mechanism of FIG. 12, on an enlarged scale; and

FIG. 14 is a cross sectional view, with portions broken away, illustrating some of the apparatus for controlling the operation of the machine.

Referring first to FIGS. 1 and 2 of the drawings, there is shown somewhat schematically a two station sheet piling machine which is supported on a frame structure including upright end frames 11 and 12 and an intermediate upright center frame 13 with a rectangular top frame 14 extending between and connecting the top portions of the three upright frames 11, 12 and 13. A pair of magnetic conveyor rail units 15, of identical construction, are supported in laterally spaced relation on the end frames 11 and 12 by cross beam structures 16. The conveyor rail units extend the full length of the machine and the cross beam structures include means for adjusting the units laterally in order to handle sheets of different widths and which extend the full length of the machine. Each of the conveyor rail units 15 includes a pair of longitudinally spaced sheaves 17 and 17 and endless belts 18 extending around the sheaves. The sheaves 17 at the one end of the units 15 are supported on a drive shaft 20 which is connected in driving relation through change speed device 21 with a driving motor 22, which shaft, change speed device and motor are supported in a suitable manner on the end frame 12. The conveyor rail units 15 are preferably of the type disclosed in U.S. Pat. No. 3,150,764, dated Sept. 29, 1964, or No. 3,199,654, dated Aug. 10, 1965. Each rail unit 15 contains electromagnets (not shown) which have downwardly facing poles and which, while energized, are adapted to hold sheets S, which are fed thereto, against the underside of the belts 18 so that the belts 18 will advance the sheets toward the right in FIGS. 1 and 2. The sheets are delivered to the magnetic conveyor rail units 15 by a feed conveyor 23 which receives them from the processing line and delivers them to the entrance end, with the magnetic conveyor ad vancing the sheets S in the same direction as the feed conveyor 23. The feed conveyor 23 has a chain and sprocket connection with a drive motor 24 mounted on the end frame 11.

Power for the magnets in the conveyor units 15 is controlled by a suitable switch arrangement including inductor switches or proximity switches which are actuated by passage of the sheets and other switch and circuit arrangements which enable automatic operation with control by the operator so as to deliver the sheets to either one of the two piling areas, which are indicated at 25 and 26, or to pass a sheet through the machine without releasing it for deposit in either one of the two piling areas 25 and 26. In each of the piling areas 25 and 26 there is disposed an identical pile receiving device which is in the form of a hoist, indicated at 27 and 27' which may be hydraulically or mechanically operated and normally supports the pile of sheets as they are released and deposited on a skid thereon by operation of the conveyor units 15. Each of the piling areas is provided with an end stop mechanism of the same construction, indicated at 28 and 28, and back stop mechanism 30 and 30, also of identical construction, the end stop mechanisms 28 and 28' being carried in depending relation on the top frame structure 14 and the back stop mechanisms 30 and 30' being supported on the forward side of the end frame structure 11, at the entrance end of the machine, and the forward side of the intermediate frame structure 13, respectively. Side edge guide mechanisms 32 and 32' are provided for the piling areas 25 and 26 which edge guide mechanisms 32 and 32' are of identical construction. The position of the end stop mechanisms 28, 28 for each of the two piling areas is controlled through connection with a longitudinal screw arrangement 33 by drive motors 34 and 35 at opposite ends of the machines, these mechanisms being supported on the top frame structure 14.

The side guide mechanisms 32 and 32' for the piling areas 25 and 26, which are of the same construction, except for being right and left hand arrangements, comprise right and left hand side guide assemblies and 40' (FIGS. 3 and 4) arranged in horizontally extending relation on opposite sides of the longitudinal center line of the machine as shown in FIGS. 3 and 4. The assembly 40 (FIGS. 5 to 8) for piling area 25 comprises a pair of vertically disposed plate members 41 and 42 which are spaced, in the direction transversely of the machine, by narrow, horizontal, top and bottom plates 43 and 44 so as to form an elongate housing 45 in which a movement equalizing shaft 46 is mounted. The shaft 46 is journaled in end plates 47 and 47' and carries on its opposite ends gear members 48 and 48 which are engageable with fixed racks 50 and 50' at opposite ends of the machine so as to insure parallel movement of the side guide assemblies 40 and 40' when they are adjusted laterally for accommodating sheets of different widths. At the entrance end of the machine (FIGS. 3 and 6) there is an adjusting screw 51, mounted in an upwardly opening housing 52 extending transversely of the machine and supported on end frame 1 1, which has right and left hand threads for connection, by means of a suitable nut arrangement 53 (FIG. 6), with the ends of the side guide assemblies 40 and 40'. The adjusting screw 51 is driven by connection with a drive motor 54 (FIG. 3) A corresponding arrangement is provided for adjusting the side guide assemblies for the piling area 26 which is operated by drive motor 54 (FIG. 1).

A supporting plate 55 extends in a plane normal to the vertically disposed plate 42 intermediate the top and bottom edges of the latter with vertically disposed bracket plates 56 which are spaced along the length of the support plate 55 as shown in FIGS. 5 to 9. The plate 55 serves to support, for reciprocating movement, a finger plate 58 disposed in parallel relation beneath the plate 55. The plate 58 is notched along its inner margin to provide a series of longitudinally spaced sheet supporting fingers 60 each provided with a pad 61 on the upper face thereof. The finger portions 60 of the plate 58 are adapted to be extended through slots 62 in the bottom portion of the innermost vertical plate 41. The inner face of plate 41 serves as an edge guide for directing the sheets down onto the pile or onto the fingers 60 when the latter are extended as shown in FIGS. 5 to 9. A supporting roller 63 is mounted on a bracket 64 on the outside margin at the bottom of the plate 41 adjacent each of the slots 62 so as to serve as a support for the plate 58. Preferably the rollers 63 are cammed on shafts which are eccentrically mounted so as to provide for some adjustment of the rollers vertically in the event there is some variation in the straightness of the plate 58 which is relatively long and may not be perfectly straight. The plate 58 is suspended beneath the support plate 55 on a plurality of bracket plates 65 (FIG. 9) which are upstanding from the outside margin of the plate 58 and which project through slots 66 spaced along the length of plate 55. Each of the suspending plates 65 carries, on Opposite faces thereof, rollers 67 and 68 arranged in paired relation with one pair disposed above the top face or surface of the plate 55 and the other pair disposed below the bottom face or surface of the plate 55 and with the plate having wear plates or wear strips 69 on which the rollers 67 and 68 ride. The slots 66 which are in the plate 55 and are ofa size to accomodate the suspension plates 65 for movement between the position shown in FIGS. 8 and 9 and a retracted position, indicated by dot and dash line in FIG. 9, where the fingers 60 are withdrawn so as to permit the sheets to be guided by the forward face of the plate 41 onto a pile below the level of the plate 58.

Reciprocating movement of the finger carrying plate 58 is had by operation of fluid cylinders 70 spaced along the length of the support plate 58, each mounted on an upstanding bracket 71 at the juncture of plates 42 and 55, by means of a pivotal connection 72 therewith, and having its piston 73 pivotally connected by pin 74 to the upstanding leg 75 of a vertically disposed, double plate, L-shaped member 76 which is attached to the outer margin of the plate 58. The plate member 76 carries a roller 77 positioned to engage a track forming wear plate member 78 mounted on the bottom face of the support plate 55. The roller 77 is mounted on an elongate shaft 79 which is common to the plate members 76 of the two reciprocating devices for the finger carrying plate 58 which are shown. The member 76 is also provided with a roller 80 of the same type as roller 63 which rides on the top surface of a support bar 81 extending from the support plate 58. The cylinder 70 is, of course, connected by lines indicated at 82 and 82' (FIG. 8) with a suitable air line or other source of fluid pressure for operation and having control valves and circuitry (not shown) for operating the same. A shock absorber device is associated with each of the cylinder assemblies which comprises a tubular housing 83 (FIG. 8) bolted or otherwise mounted on the bottom face of the support plate 58 with slidable pistons 84, 84 at opposite ends of the housing 83 which are backed by spring members 85 in the housing 83 and which are positioned to be engaged by the vertical faces of spaced bumper pad assemblies 86 and 86' mounted in the ends of a rectangular support frame 87 which support frame is bolted or otherwise secured on the bottom face of the support plate 58 along the side of the frame assembly 76. The pad assemblies 86, 86 may be metal face plates backed by rubber pads or other resilient pad material. Finger limit control switches 88 and 86 (FIG. 5) are mounted in spaced relation on the support plate 58 for operation by a cam member 88" extending from a suspension plate 65 to control the operation of cylinders 70 and insure proper projection and retraction of the fingers 60.

Each of the back stop plates 30 and 31) (FIGS. 2, 3 and extends upwardly to a brake device 89 which is operative to attract the trailing ends of the sheets and to slow down the advance of the sheets as they are released by the conveyor units for deposit on the pile. The braking units 85 are of the character described in US. Pat. No. 3,172,526, dated Mar. 9, 1965. Each of the back stop plates 30 and 30' has an associated, reciprocably mounted finger 90, as shown in FIG. 10, for

co-operation with the supporting fingers 60 on the side guide assemblies 40, which is adapted to be projected into the position shown for supporting the trailing ends of the plates temporarily while the previously accumulated stack is being removed from the machine. The finger 90 is mounted on the end of a slide support 91 and adapted to project through a slot 92 provided in the vertically disposed back stop plate 30. The bracket forming member 91 is supported in sliding relation on the top of housing 52. The plate 91 is connected to an elongate box-like carriage 93 having rollers 94 on its oppositely disposed side faces which are received in track forming channels 95 mounted by means of brackets 96 on the end frame structure 11. A fluid operated cylinder 97 is pivotally mounted at 98 on a supporting bracket 100 fixed on the frame 11, and has its piston 101 connected to the carriage frame 93. The cylinder 97 is connected for operation to an air line or other fluid pressure source with control valve and circuitry arrangement so as to reciprocate the carriage 93 and thus move the sheet supporting finger 90 into and out of sheet supporting position.

Each of the end stop devices 28 and 28 is constructed and supported in the same manner. The end stop device 28 (FIGS. 11 to 13) comprises a cross frame riding on the top frame structure 14. The cross frame 110 has rollers 111 and 112 at each side thereof which ride on the top and bottom of frame side members 113 and 114 and carry depending linkages 115 on the lower end of which there is a support plate 116. The support plate 116 has on its lower face depending spaced brackets 117 and 117 carrying on opposed faces thereof rollers 118, 118' which ride in track forming channel members 120, 120' on the outside faces of a rec-tangular frame 121 on the end of which there is supported a bumper pad assembly 122. The bumper pad assembly 122 is mounted on the forward end of the frame 121 by means of a vertically extending pivot pin 123. The reciprocable frame 121 is open at the top and an air cylinder 124 is mounted on brackets 125 depending from the support plate 116 with its piston 126 connected at 127 to the forward end 128 of the sliding frame 121. The cylinder 124 is connected to a suitable source of compressed air or other fluid pressure so as to permit limited movement horizontally of the bumper pad assembly 122 when it is struck by the forward edge of an advancing sheet. The bottom margin of the bumper pad assembly 122 is notched at 130 to accommodate a reciprocably mounted sheet supporting finger 1131 which is carried on a support bar 132 extending from the bottom face of an elongate box-like carriage 133. The carriage 133 has rollers 134 on its oppositely disposed vertical faces which ride in track forming channels 135 which are mounted by means of brackets 1136 on the bottom of the brackets 117 and 117. A fluid cylinder 137 is mounted on a cross pin 138 extending between the channels 135, 135' and has its piston 140 connected to the forward end of the reciprocating frame 133 with a suitable connection to an air line or other fluid pressure source for reciprocating the finger 131 between an extended position where it will support a sheet S and a retracted position which permits the sheet to drop to the pile below.

The machine is provided with automatic control and safety features which include photocell and proximity switches with suitable electric control circuitry. In FIG.

l4 proximity switches 150, 150 are provided on the back stop plate 30 at the entrance end of the piling area 25 to detect the edges of the sheets piled on the fingers 60, 90 and 131. A photocell light beam, indicated at 151, is directed across the piling area at a level below the fingers 60 which serves as a level control for the hoist. Normal piling on the hoist will not go above the level of beam 151 which may be directed through suitable apertures in the side guide plates 41. The light beam 151 determines when the height of a pile on the hoist constitutes a full pack, ready for removal. When a full pack is made, the fingers 60, 90 and 131 are extended and the succeeding sheets fall on the fingers. Then the hoist is lowered, the pack thereon is removed and with a new skid in place the hoist is raised until the skid raises the pile of sheets, which have accumulated on the fingers, upwardly of the fingers so that the fin gers are freed and may be retracted. The proximity switches 150,150 are connected into the control circuitry so that upon the sheets being raised above the fingers, the fingers will be retracted and normal piling on the hoist will be resumed. A photocell beam, indicated at 152 is provided at a level above the level of the fingers 60, 90 and 131 which extends across the piling area and serves to limit the height of a pile supported on the fingers so as to protect the fingers against overloading. The beam 152 may be directed through suit able apertures in the side guide plates 41 and 42. When the sheets have accumulated on the fingers to a height which blocks the beam 152 the machine is brought to a stop. The pack on the hoist must be removed and the hoist repositioned to take the accumulated sheets on the fingers before the beam 152 is blocked in order to keep the machine in continuous operation.

I claim:

1. A sheet piling machine comprising an upright support frame, an overhead conveyor mounted on said support frame, said conveyor having means for forwarding metal sheets on the bottom surface thereof and releasing the same for deposit on a pile in a pile forming area beneath the conveyor, a pile support member in said piling area with means for raising and lowering the same, a fixed back stop member at the entrance end of the piling area providing a vertical guide surface at a fixed point for the trailing edge of the sheets, a temporary sheet supporting member mounted at a substantial distance below said conveyor bottom surface for horizontal sliding movement relative to the vertical guide surface of said back stop member between an extended position where it is operative to support sheets released by the conveyor and a retracted inoperative position, power drive means for moving said temporary sheet supporting member between said operative and inoperative positions, an end stop mechanism having a carriage forming frame adjustably mounted on said support frame so as to be adjustably positioned in longitudinally spaced relation to said back stop member, said end stop mechanism including a horizontally cushioned bumper pad assembly providing a vertical surface positioned for engagement by the leading edge of the sheets as they are released by the conveyor and settle onto a pile on said pile support member and a temporary sheet supporting member mounted on said carriage forming frame for horizontal sliding movement adjacent the bottom edge of said bumper pad assembly between an extended sheet supporting position and a retracted non-supporting position, power drive means for moving said temporary sheet supporting member on said end stop mechanism between said sheet supporting and nonsupporting positions, and sheet side edge guiding mechanisms mounted on said support frame on opposite sides of the path of advance of the sheets and ex tending between the back stop member and the end stop mechanism which provide oppositely disposed vertical sheet edge engaging surfaces, a plurality of temporary sheet supporting members slidingly mounted in relatively close, longitudinally spaced rela tion on said side edge guiding mechanisms, a common support member for said temporary side edge sheet supporting members on each of said side edge guiding mechanism, said common support members being mounted for horizontal sliding movement above the bottom edges of said side edge guiding mechanisms, roller support means mounted immediately adjacent the vertical sheet edge engaging surfaces of said side edge guiding mechanisms on which said temporary sheet supporting members ride, drive means for said common support members which is operable to move said temporary side edge sheet supporting members between a retracted nonoperating position and a position extending horizontally into the piling area in a plane at a predetermined elevation above the bottom thereof which corresponds to the elevation of the temporary sheet supporting members on the back stop member and on the end stop mechanism, thereby providing for temporarily supporting thereon a pile of sheets at points spaced around the peripheral margins of the sheets, means for sensing the height of a pile of sheets on said pile support in said piling area and means for actuating the drive means for said temporary sheet supporting members which is responsive to said sensing means to thereby position said temporary sheet supporting members for receiving the sheets thereon when the pile on the pile support reaches a predetermined height.

2. A sheet piling machine as set forth in claim 1 wherein said common support member for said temporary sheet supporting members on said side edge guiding mechanisms comprises an elongate carriage forming support plate which extends lengthwise on the machine, roller means on the associated side edge guiding mechanism for supporting said carriage plate and the temporary sheet supporting members thereon for reciprocating movement in a horizontal plane, said side edge guiding mechanism having a vertical edge guiding surface with longitudially spaced slots along the bottom margin for receiving said temporary sheet supporting members, and power means for moving said carriage plate between an extended position where the temporary sheet supporting members are disposed relative to the associated sheet edge engaging surface in sheet supporting relation and a retracted inoperative position permitting the sheets to drop onto a pile below the level of the support fingers.

3. A sheet piling machine as set forth in claim 1 wherein the temporary sheet supporting member on said end stop mechanism includes a support finger, a carriage forming frame on which said support finger is mounted, horizontal track means for said carriage forming frame, and fluid operated drive means for moving said carriage to project said support finger into a position where it extends in a plane normal to the sheet edge engaging surface of said end stop member so as to support the leading end of a sheet and to retract said support finger to an inoperative non-supporting position. 

1. A sheet piling machine comprising an upright support frame, an overhead conveyor mounted on said support frame, said conveyor having means for forwarding metal sheets on the bottom surface thereof and releasing the same for deposit on a pile in a pile forming area beneath the conveyor, a pile support member in said piling area with means for raising and lowering the same, a fixed back stop member at the entrance end of the piling area providing a vertical guide surface at a fixed point for the trailing edge of the sheets, a temporary sheet supporting member mounted at a substantial distance below said conveyor bottom surface for horizontal sliding movement relative to the vertical guide surface of said back stop member between an extended position where it is operative to support sheets released by the conveyor and a retracted inoperative position, power drive means for moving said temporary sheet supporting member between said operative and inoperative positions, an end stop mechanism having a carriage forming frame adjustably mounted on said support frame so as to be adjustably positioned in longitudinally spaced relation to said back stop member, said end stop mechanism including a horizontally cushioned bumper pad assembly providing a vertical surface positioned for engagement by the leading edge of the sheets as they are released by the conveyor and settle onto a pile on said pile support member and a temporary sheet supporting member mounted on said carriage forming frame for horizontal sliding movement adjacent the bottom edge of said bumper pad assembly between an extended sheet supporting position and a retracted non-supporting position, power drive means for moving said temporary sheet supporting member on said end stop mechanism between said sheet supporting and nonsupporting positions, and sheet side edge guiding mechanisms mounted on said support frame on opposite sides of the path of advance of the sheets and extending between the back stop member and the end stop mechanism which provide oppositely disposed vertical sheet edge engaging surfaces, a plurality of temporary sheet supporting members slidingly mounted in relatively close, longitudinally spaced relation on said side edge guiding mechanisms, a common support member for said temporary side edge sheet supporting members on each of said side edge guiding mechanism, said common support members being mounted for horizontal sliding movement above the bottom edges of said side edge guiding mechanisms, roller support means mounted immediately adjacent the vertical sheet edge engaging surfaces of said side edge guiding mechanisms on which said temporary sheet supporting members ride, drive means for said common support members which is operable to move said temporary side edge sheet supporting members between a retracted nonoperating position and a position extending horizontally into the piling area in a plane at a predetermined elevation above the bottom thereof which corresponds to the elevation of the temporary sheet supporting members on the back stop member and on the end stop mechanism, thereby providing for temporarily supporting thereon a pile of sheets at points spaced around the peripheral margins of the sheets, means for sensing the height of a pile of sheets on said pile support in said piling area and means for actuating the drive means for said temporary sheet supporting members which is responsive to said sensing means to thereby position said temporary sheet supporting members for receiving the sheets thereon when the pile on the pile support reaches a predetermined height.
 2. A sheet piling machine as set forth in claim 1 whereIn said common support member for said temporary sheet supporting members on said side edge guiding mechanisms comprises an elongate carriage forming support plate which extends lengthwise on the machine, roller means on the associated side edge guiding mechanism for supporting said carriage plate and the temporary sheet supporting members thereon for reciprocating movement in a horizontal plane, said side edge guiding mechanism having a vertical edge guiding surface with longitudially spaced slots along the bottom margin for receiving said temporary sheet supporting members, and power means for moving said carriage plate between an extended position where the temporary sheet supporting members are disposed relative to the associated sheet edge engaging surface in sheet supporting relation and a retracted inoperative position permitting the sheets to drop onto a pile below the level of the support fingers.
 3. A sheet piling machine as set forth in claim 1 wherein the temporary sheet supporting member on said end stop mechanism includes a support finger, a carriage forming frame on which said support finger is mounted, horizontal track means for said carriage forming frame, and fluid operated drive means for moving said carriage to project said support finger into a position where it extends in a plane normal to the sheet edge engaging surface of said end stop member so as to support the leading end of a sheet and to retract said support finger to an inoperative non-supporting position. 